The invention concerns a hydraulic vane machine with a rotor, having several radially movable vanes, with a stator having a stator bore, in which the rotor is arranged rotatably, and whose internal wall is made as a guiding contour on which the vanes bear, and with a sideplate arrangement on each axial front side of rotor and stator, which limit the vane cells together with the rotor, the vanes and the stator.
Such machines can both be made as motors (U.S. Pat. No. 4,376,620 and U.S. Pat. No. 3,254,570) and as pumps (U.S. U.S. Pat. No. 3,255,704). On a rotor rotation in relation to the stator, the vanes move radially inwards and outwards, by which the movement is controlled by the guiding contour. For this purpose the guiding contour has resting areas, in which the stator bore has a diameter only slightly larger than the outside diameter of the rotor, and working areas, in which the stator bore has a larger diameter. Commutation areas are arranged between the resting areas and the working areas, in which the vanes are moved radially from the inside to the outside or from the outside to the inside, respectively. In this connection the bearing of the vanes on the guiding contour is effected by springs. However, in most cases an additional hydraulic support is used to increase the bearing pressure of the vanes on the guiding contour.
Even though the principle, as mentioned above, can be used for both pumps and motors, the following description is, for convenience, based on a motor.
In the working areas the high pressure side of the vanes is admitted with hydraulic fluid under increased pressure. The low pressure side of the vanes is exposed to a lower pressure. The pressure difference across the vanes produces the required torque for the driving of the motor. In some cases it may happen that a closed vane cell is placed between the high pressure and the low pressure connection of the machine. In this case the pressure difference across two or more vanes will apply.
Like in all hydraulic machines it is important that the internal leakages are kept small, i.e. that the machine is also tight inside. In this connection areas, in which sealing between movable parts is required, cause particular problems.
In a vane machine, this is primarily the case with the bearing of the vane on the guiding contour. Additionally, the vane cells must also be sealed towards the side. In the known cases, there is both the friction between the rotor and the sideplates and the friction between the vanes during their radial movement and the side plates. As considerable pressures are applied for the provision of the tightness, each of these movements causes a wear and thus deteriorates the performance, particularly when hydraulic fluids are used, whose lubricating effect is poorer than that of the synthetic hydraulic oils used until now. Such a fluid could e.g. be water.
It is the purpose of the invention to improve the performance of a hydraulic vane machine.